1. Field of Invention
The present invention relates to a multi-functional feed-screw-type dovetail stage. More particularly, the present invention relates to a feed-screw-type dovetail stage in which a slide member having a female-threaded cylinder connected thereto is engaged with a fixed member having a male-threaded rod connected thereto, and, by operating a control knob to rotate the male-threaded rod so as to move the female-threaded cylinder, the slide member is made to slide to thereby perform positional adjustment of a precision apparatus mounted on the stage.
2. Description of Related Art
When installing precision apparatuses, such as electric or electronic devices including CCD cameras and sensors, optical devices including lenses and microscopes, and illumination devices including LEDs, positional adjustment must be performed in order to determine proper positioning and to achieve focus. Further, after installation in position, additional fine positional adjustments may become necessary.
Such precision apparatuses are often mounted on a device called a “dovetail stage” and subjected to positional adjustment. In a typical structure of a dovetail stage, a slide member for mounting an apparatus thereon is coupled, by means of a slide mechanism, to a fixed member secured to a base, and, by manually operating a control knob, the slide member is made to slide with respect to the fixed member. There are various formats of such a dovetail stage provided for different purposes of use. For example, a dovetail stage may be an X-axis dovetail stage that slides in one direction, an XY-axis dovetail stage that slides in two substantially orthogonal directions, a Z-axis dovetail stage that slides along the vertical direction, or a rotary stage that slides in rotation. Further, depending on the incorporated drive system, a dovetail stage may be, for example, a feed-screw-type dovetail stage that is driven by a feed screw, or a rack-and-pinion-gear-type dovetail stage that is driven by a rack and pinion gear.
FIGS. 9(a)-9(c) show a conventional feed-screw-type dovetail stage. FIG. 9(b) shows a side view of a feed-screw-type dovetail stage 100. FIG. 9(a) shows a plan view of the structure of FIG. 9(b) as viewed in the direction indicated by G-G. FIG. 9(c) is a plan view of the structure of FIG. 9(b) as viewed in the direction indicated by H-H. The feed-screw-type dovetail stage 100 is composed of a slide member 103 having a dovetail 104, a fixed member 102 having a dovetail groove 105, a male-threaded rod 107 and a female-threaded cylinder 106 constituting the slide mechanism, a control knob 108, and a slide lock screw 112. A scale plate 113b is provided on the slide member 103 side, while a scale plate 113a is provided on the fixed member 102 side. By engaging the male-threaded rod 107 with the female-threaded cylinder 106 and rotating the control knob 108, the slide member 103 slides with respect to the fixed member 102. The slide lock screw 112 serves to lock the slide member 103 with respect to the fixed member 102 at an arbitrary position.
The male-threaded rod 107 of the feed-screw-type dovetail stage 100 has a cantilever structure, with one end being mounted and attached to the fixed member 102 and the other end being a free end. In the feed-screw-type dovetail stage 100, the range of travel of the slide member 103 with respect to the fixed member 102 is defined by abutment of the female-threaded cylinder 106 against a stopper plate 109 attached to one end of the fixed member 102 and a washer 110 provided at the other end of the fixed member 102. The male-threaded rod 107 constitutes an integral part of the feed-screw-type dovetail stage 100, and therefore cannot be replaced. Further, owing to the mechanism of the feed-screw-type dovetail stage 100, the positions of the control knob 108 and the scale plates 113a, 113b are fixed.
A rotary stage having a rotary table that rotates with respect to a base is also conventionally known. In a rotary stage, a feed screw is provided on one of the rotary table or the base, while a nut that screws onto the feed screw is provided on the other component. By means of this feed screw mechanism, the rotary table rotates in both forward and reverse directions with respect to the base.
In a conventional feed-screw-type dovetail stage, the male-threaded rod has a cantilever structure with one end being fixed and the other end being a free end, such that the male-threaded rod has a larger deflection toward its tip due to its own weight. Accordingly, distorted engagement may be generated between the female-threaded cylinder and the male-threaded rod as the length of the female-threaded cylinder becomes longer, possibly resulting in degraded performance of the feed-screw-type dovetail stage.
Furthermore, the male-threaded rod and the control knob are provided in a fixed manner and constitute an integral part of the feed-screw-type dovetail stage product. Accordingly, a user cannot replace the male-threaded rod, such that the stage has very limited functionality.
Moreover, as the positions of the control knob, slide lock screw, and scale plates are fixed in the product, those positions cannot be changed. Also, the structure of the stage does not permit a user to select the travel range of the slide member from a variety of different ranges. Therefore, a conventional stage has poor usability for the user.